JP2009506839A - Catheter with adjustable stiffness - Google Patents

Abstract

  A medical device, such as a catheter, may comprise a structure or facility that allows a physician or other health care professional to adjust the stiffness of at least a portion of the medical device. In some cases, the medical device can be adjusted prior to inserting the medical device into a patient. Also, in some cases, the medical device can be adjusted while in use in the patient's body.

Description

  The present invention relates generally to medical devices such as catheters, and more particularly to catheters with structures or facilities that provide adjustable stiffness.

  Medical devices such as catheters are subject to numerous conflicting performance requirements, such as flexibility and strength. In some cases, improved flexibility can be obtained at the cost of reduced strength. Also, an increase in strength can be obtained at the expense of reduced flexibility. Because each patient is different, there may be a unique balance of performance parameters such as flexibility and strength that is optimal for a particular patient.

  While it is certainly possible to construct a large number of catheters corresponding to any feasible set of desired performance parameters, this will probably be prohibitively expensive. Further, in some cases, the physician may determine that a certain balance of stiffness versus flexibility is required during the procedure. Accordingly, there remains a need for medical devices such as catheters that can be adjusted with respect to their stiffness, especially in situ.

  The present invention has been made in view of the above-mentioned concerns.

  The present invention generally relates to a medical device, such as a catheter, with a structure or facility that allows a physician or other health care professional to adjust the stiffness of at least a portion of the medical device. In some cases, the medical device may be adjusted prior to insertion into the patient's body. Also, in some cases, the medical device may be adjusted while in use within the patient's body.

  Accordingly, an exemplary embodiment of the present invention includes an elongate polymer shaft that extends from the proximal region of the catheter to the distal region of the catheter, and a first spiral cut disposed within the elongate polymer shaft. And is shown as an adjustable catheter with a hypotube.

  Another exemplary embodiment of the present invention is shown as an adjustable catheter having an elongate polymer shaft that defines a lumen extending from the proximal region of the catheter to the distal region of the catheter. A first inflatable tube extending from the proximal region to the distal region and arranged at least approximately parallel to the longitudinal axis of the catheter is disposed within the lumen. By inflating the first inflatable tube, the rigidity of the elongated polymer shaft is increased.

  Another exemplary embodiment of the present invention is shown as an adjustable catheter comprising an inner polymer liner, an outer polymer liner, and a swellable layer disposed between the inner and outer polymer liners. By adding an appropriate fluid to the swellable layer, the adjustable catheter stiffness is increased.

  Another exemplary embodiment of the present invention is shown as an adjustable catheter having an elongated polymer shaft that extends from the proximal region to the distal region of the catheter. On the long polymer shaft, a rigidity enhancing sheath having higher rigidity than the long polymer shaft is slidably disposed.

  Another exemplary embodiment of the present invention is shown as an adjustable catheter with an elongate polymer shaft that extends from the proximal region of the catheter to the distal region of the catheter and includes a wall. Within the wall, a number of elongated openings are arranged in the elongated polymer shaft such that the openings extend longitudinally. A large number of stiffness enhancing filaments are slidably disposed in each of the large number of elongated openings.

  Another exemplary embodiment of the present invention is shown as an adjustable catheter having an inner polymer layer with one or more electrically actuated stiffness enhancements. An outer polymer layer is disposed on the inner polymer layer.

  Another exemplary embodiment of the present invention is shown as an adjustable catheter with a long, rigid polymer shaft. The rigidity of the long polymer shaft can be changed by passing a current through the long polymer shaft.

  The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The following drawings, detailed description and examples illustrate these embodiments in more detail.

The present invention may be more fully understood with reference to the following detailed description of various embodiments of the invention in connection with the accompanying drawings.
While the invention is susceptible to various modifications and alternative forms, specifics thereof are shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
In this application, all numerical values are considered to be modified by the word “about”, whether or not explicitly indicated. The term “about” generally refers to a series of numbers that one of ordinary skill in the art deems equivalent to the recited value (ie, has the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numbers within that range (eg 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” refer to a number of instructions unless the content clearly indicates otherwise. Include. As used herein and in the appended claims, the term “or” is generally used in its sense including “and / or” unless the content clearly dictates otherwise. Is done.

  The following description should be read in conjunction with the drawings. In the drawings, like reference numerals indicate like elements throughout the several views. The drawings are not necessarily to scale, but represent illustrative embodiments of the claimed invention.

  FIG. 1 is a plan view of a catheter 10 according to an embodiment of the present invention. Catheter 10 can be any of a variety of different catheters. In some embodiments, the catheter 10 can be an intravascular catheter. Examples of intravascular catheters include balloon catheters, atherectomy catheters, drug delivery catheters, stent delivery catheters, diagnostic catheters, and guide catheters. Intravascular catheter 10 may be sized according to its intended use. Catheter 10 has a length in the range of about 100-150 centimeters and can have any useful diameter. Although FIG. 1 shows a guide catheter, the present invention is not limited to a guide catheter. Except as specifically described herein, the intravascular catheter 10 can be manufactured using conventional techniques.

  In the illustrated embodiment, the intravascular catheter 10 includes an elongate shaft 12 having a proximal region 14 that defines a proximal end 16 and a distal region 18 that defines a distal end 20. A hub and strain relief assembly 22 may be coupled to the proximal end 16 of the elongate shaft 12. The hub and strain relief assembly 22 may be of a conventional type and may be attached using conventional techniques. Other hub types can be incorporated into embodiments of the present invention.

  The elongate shaft 12 may comprise one or more shaft segments having different flexibility. For example, the elongate shaft has a relatively rigid proximal end portion, a relatively flexible distal end portion, and an intermediate flexible proximal end portion and distal end relative to both. And an intermediate portion disposed between the side portions.

  In some cases, the elongate shaft 12 may be formed from a single polymer layer. Further, the long shaft 12 may include an inner liner such as an inner slipping layer and an outer layer. Further, the elongated shaft 12 may include a reinforcing braid layer disposed between the inner layer and the outer layer. The elongate shaft 12 is considered herein generically to represent a catheter to which various elements can be added to provide the catheter 10 with adjustable stiffness.

  Where the elongate shaft 12 comprises an inner liner, the inner liner can include or be formed from a coating of a material having a suitable low coefficient of friction. Examples of suitable materials include perfluoropolymers such as polytetrafluoroethylene (PTFE), better known as Teflon, high density polyethylene (HDPE), polyarylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol, Examples include hydroxyalkyl cellulose compounds, algins, sugars, caprolactone, and the like, and mixtures and combinations thereof.

  The elongate shaft 12 may contain any suitable polymer that provides the desired strength, flexibility, or other desired characteristics as one or more outer layers. A polymer with a low durometer or hardness provides great flexibility, while a polymer with a high durometer or hardness can give high rigidity. In some embodiments, the polymer material used is a thermoplastic polymer material. Some examples of suitable materials include polyurethane, elastic polyamide, block polyamide / ether (such as PEBAX®), silicones and copolymers. The outer polymer layer 32 can be a single polymer, multiple longitudinal sections or layers, or a blend of polymers. By careful selection of materials and processing techniques, the thermoplastic, solvent soluble, and thermosetting variations of these materials can be used to achieve the desired results. In some cases, a thermoplastic polymer such as a copolyester thermoplastic elastomer commercially available under the name ARNITEL® may be used.

  FIG. 2 shows an assembly 24 with a hypotube 26 disposed within the polymer layer 28. For exemplary purposes only, the polymer layer 28 is shown as a single layer in phantom lines. In some cases, the polymer layer 28 may be two or more polymer layers. Any suitable polymer can be used. The assembly 24 may also include one or more polymer layers, such as a slippery layer, within the hypotube 26.

  The hypotube 26 can be cut to obtain flexibility. In some cases, as shown, the hypotube 26 may be a helically cut hypotube having a helically aligned cut or cut 30 that separates adjacent bridge portions 32. While the notch 30 provides flexibility, the bridge portion 32 allows the hypotube 26 to retain a certain level of strength. The hypotube 26 may be formed from any suitable polymer or metal material. Optionally, the hypotube 26 may be formed from laser cut stainless steel.

  Each of the incisions 30 is shown to have a specific width. FIG. 2 shows the hypotube 26 in a relaxed configuration, ie, when no external force is applied to the hypotube 26. The relative dimensions of the notch 30 and the bridge portion 32 provide the hypotube 26 and thus the assembly 24 with a given balance of flexibility versus strength.

  In FIG. 3, the assembly 24 is stiffened by reducing the relative size of each of the cuts 34 while each of the bridge portions 32 remains unchanged. This can be done, for example, by applying a compressive force to the hypotube 26 as indicated by the arrow 36. Alternatively, this can be done by rotating the hypotube 26 as indicated by arrow 38. Although not specifically shown, it is possible to change the diameter of the hypotube 26 by applying either a compressive force or a rotational force to the hypotube 26.

  In some cases, for example, as shown in FIGS. 4-6, the catheter may comprise two or more hypotubes that are coaxially aligned. FIG. 4 is a schematic cross-sectional view of assembly 40 showing inner hypotube 42, outer hypotube 44, and polymer layer 46. The polymer layer 46 can be formed from any suitable polymer. Although not specifically shown, both the inner hypotube 42 and the outer hypotube 44 may be cut in a spiral shape. Inner hypotube 42 and outer hypotube 44 may each be formed from any suitable polymer or metal material. Optionally, the inner hypotube 42 and the outer hypotube 44 may each be formed from laser cut stainless steel.

  An annular gap 48 is seen between the inner hypotube 42 and the outer hypotube 44. It should be noted that FIG. 4 is not to scale, rather, certain elements are exaggerated for clarity. The inner hypotube 42 is considered to have an outer diameter that is slightly smaller than the inner diameter of the outer hypotube 44. The inner hypotube 42 together with any desired inner layer or layers (not shown) forms a lumen 50 suitable for any desired or necessary medical procedure.

  The annular gap 48 provides at least some relative movement between the inner hypotube 42 and the outer hypotube 44 before interference between the inner hypotube 42 and the outer hypotube 44 reduces the flexibility of the assembly 40. Can be tolerated. FIG. 4 shows the relaxed configuration, ie, no external force is applied to any part of the assembly 40.

  However, in FIG. 5, the inner hypotube 42 is expanded relative to the outer hypotube 44 such that the annular gap 48 (shown in FIG. 4) is at least substantially eliminated. This can be done, for example, by rotating the inner hypotube 42 to increase the diameter of the inner hypotube 42. Optionally, the inner hypotube 42 may extend proximally of the proximal region 14 (see FIG. 1) to allow the operator to rotate the inner hypotube 42; Alternatively, it may be operatively connected to an operating structure extending to the proximal side of the proximal region 14.

  Conversely, the outer hypotube 44 is contracted in diameter relative to the inner hypotube 42 so that a new annular gap 52 appears between the outer hypotube 44 and the polymer layer 46, as shown in FIG. May be. This can be done, for example, by rotating the outer hypotube 44 to reduce the diameter of the outer hypotube 44. Optionally, the outer hypotube 44 may extend proximally of the proximal region 14 (see FIG. 1) to allow an operator to rotate the outer hypotube 44, Alternatively, it may be operatively connected to an actuation structure extending proximally of the proximal region 14.

  7-12 illustrate an embodiment of the present invention in which an inflatable element is deployed within the catheter to provide adjustable stiffness. In FIG. 7, the catheter 54 includes an elongate shaft 56. As discussed above with respect to FIG. 1, the elongate shaft 56 may be a polymer shaft and may comprise a single polymer layer, two polymer layers, or several polymer layers, reinforcement layers, and the like. The lumen 58 extends through the interior of the elongate shaft 56, and the elongate shaft 56 may be formed from any suitable one or more polymers.

  An elongate inflation tube 60 is disposed within the lumen 58. In some cases, the elongated inflation tube 60 may be integrally formed within the elongated shaft 56. In some cases, the elongated inflation tube 60 may be formed independently and subsequently secured within the lumen 58 using any suitable attachment technique. As shown in FIG. 7, the elongated inflation tube 60 contracts. The elongate inflation tube 60 can be formed from any suitable one or more polymers.

  In FIG. 8, the elongated inflation tube 60 is inflated. The elongated inflation tube 60 can extend from the proximal region 62 to the distal region 64 over at least approximately the entire length of the elongated shaft 56. In some cases, the elongated inflation tube 60 may extend sufficiently proximally to communicate with the hub 22 (see FIG. 1), thereby introducing inflation fluid into the elongated inflation tube 60. It is. Saline is a typical fluid, but any suitable fluid may be used. Saline is biocompatible, which is important when rupture occurs. Furthermore, as an aqueous solution, saline is generally incompressible.

  In the illustrated embodiment, the elongate inflation tube 60 has a radial cross section that is at least approximately circular in shape and remains at least approximately constant over the length of the elongate inflation tube 60. In some cases, it is contemplated that the elongated inflation tube 60 may have a non-circular radial cross section. For example, the elongate inflation tube 60 may have an oval or polygonal radial cross section.

  In some cases, it is contemplated that the elongated inflation tube 60 may have a radial cross section that varies in size over its length. For example, the elongate inflation tube 60 may have a smaller radial cross section in the distal region 64 and a larger radial cross section in the proximal region 62. Optionally, the elongate inflation tube 60 may have two, three, or more individual regions, each region having a unique radial cross-sectional size and / or shape.

  It can be seen that the elongated inflation tube 60 has a relatively small impact on the flexibility of the elongated shaft 56 when contracted. However, when the elongate inflation tube 60 is inflated or pressurized, the elongate shaft 56 may be relatively less flexible or relatively more rigid. It is done.

  FIG. 9 shows a catheter 66 with an elongate shaft 68. The elongate shaft 68 may be a polymer shaft and may comprise a single polymer layer, two polymer layers, or several polymer layers, reinforcement layers, and the like. Lumen 70 extends through the interior of elongate shaft 68, and elongate shaft 68 may be formed from any suitable one or more polymers.

  A first elongate inflation tube 74 and a second elongate inflation tube 72 are disposed in the lumen 70. In some cases, the first elongated inflation tube 74 and the second elongated inflation tube 72 may be integrally formed within the elongated shaft 68. Optionally, the first elongate inflation tube 74 and the second elongate inflation tube 72 may be formed independently and subsequently secured within the lumen 68 using any suitable attachment technique. . Each of the first elongate inflation tube 74 and the second elongate inflation tube 72 may be formed from any suitable material.

  As indicated, the first elongate inflation tube 74 and the second elongate inflation tube 72 are inflated or pressurized and at least substantially parallel to each other. In some cases, the first elongate inflation tube 74 and the second elongate inflation tube 72 may be disposed at an angle with respect to each other. Each of the first elongate inflation tube 74 and the second elongate inflation tube 72 can extend over at least approximately the entire length of the elongate shaft 68 from the proximal region 76 to the distal region 78.

  Optionally, the first elongated inflation tube 74 and the second elongated inflation tube 72 each extend sufficiently proximally to communicate with the hub 22 (see FIG. 1), thereby expanding the It is possible to introduce a fluid. Saline is a typical fluid, but any suitable fluid may be used.

  In FIG. 10, the catheter 80 is shown to include an elongate shaft 82. The elongate shaft 82 may be a polymer shaft and may comprise a single polymer layer, two polymer layers, or several polymer layers, reinforcing layers, and the like. Lumen 84 extends through the interior of elongate shaft 82, and elongate shaft 82 may be formed from any suitable one or more polymers.

  A first elongate inflation tube 86 and a second elongate inflation tube 88 are disposed in the lumen 84. In some cases, the first elongated inflation tube 86 and the second elongated inflation tube 88 may be integrally formed within the elongated shaft 82. Optionally, the first elongate inflation tube 86 and the second elongate inflation tube 88 may be formed independently and subsequently secured within the lumen 68 using any suitable attachment technique. . Each of the first elongate inflation tube 86 and the second elongate inflation tube 88 may be formed from any suitable one or more polymers.

  As shown, the first elongate inflation tube 86 and the second elongate inflation tube 88 are inflated or pressurized. The second elongate inflation tube 88 is shown extending from at least approximately the entire length of the elongate shaft 82 from the distal region 90 to the proximal region 92. However, the first elongate inflation tube 86 ends at an appropriate position 94 before the tip region 90. In some cases, it may be desirable to temporarily provide additional stiffness to the proximal region 92 while maintaining a relatively higher level of flexibility within the distal region 90.

  In some cases, the first elongate inflation tube 86 and the second elongate inflation tube 88 each extend sufficiently proximally to communicate with the hub 22 (see FIG. 1), thereby inflating. It becomes possible to introduce a fluid. Saline is a typical fluid, but any suitable fluid may be used.

  FIG. 11 shows a catheter 96 with an elongate shaft 98. The elongate shaft 98 may be a polymer shaft and may comprise a single polymer layer, two polymer layers, or several polymer layers, reinforcement layers, and the like. The lumen 100 extends through the interior of the elongate shaft 96, and the elongate shaft 98 can be formed from any suitable one or more polymers.

  Within the lumen 100, an elongate annular inflation ring 102 is provided. In some cases, the elongated annular expansion ring 102 may be integrally formed within the elongated shaft 98. In some cases, the elongated annular inflation ring 102 may be formed independently and subsequently secured within the lumen 100 using any suitable attachment technique. The elongate annular expansion ring 102 can be formed from any suitable one or more polymers.

  As shown, the elongated annular space expansion ring 102 is inflated or pressurized. The elongate annular expansion ring 102 may extend at least approximately the entire length of the elongate shaft 98 from the proximal region 104 to the distal region 106. In some cases, the elongate annular inflation ring 102 extends sufficiently proximal to communicate with the hub 22 (see FIG. 1), thereby introducing inflation fluid into the elongate annular inflation ring 102. It becomes possible. Saline is a typical fluid, but any suitable fluid may be used.

  FIG. 12 shows a catheter 108 with an elongate shaft 110. The elongate shaft 110 may be a polymer shaft and may comprise a single polymer layer, two polymer layers, or several polymer layers, reinforcement layers, and the like. The lumen 112 extends through the interior of the elongate shaft 110, and the elongate shaft 110 can be formed from any suitable one or more polymers.

  Within the lumen 112, an elongate inflation ring 114 is provided. In some cases, the elongated inflation ring 114 may be integrally formed within the elongated shaft 110. Optionally, the elongated inflation ring 114 may be formed independently and subsequently secured within the lumen 112 using any suitable attachment technique. The elongated inflation ring 114 can be formed from any suitable one or more polymers.

  The elongated annular expansion ring 102 (FIG. 11) has at least a substantially constant dimension. In contrast, elongate inflation ring 114 has varying dimensions. In some cases, the elongated inflation ring 114 may have a relatively thinner dimension along one side (top in the figure) and a relatively thicker dimension along the other side (bottom in the figure). This is useful when it is desired to provide relatively greater stiffness along one side of the catheter 108 and to provide relatively reduced stiffness along the other side of the catheter 108.

  As shown, the elongated inflation ring 114 is inflated or pressurized. The elongate expansion ring 114 may extend over at least approximately the entire length of the elongate shaft 110 from the proximal region 116 to the distal region 118. In some cases, the elongated inflation ring 114 may extend sufficiently proximal to communicate with the hub 22 (see FIG. 1), thereby introducing inflation fluid into the elongated inflation ring 114. It becomes possible. Saline is a typical fluid, but any suitable fluid may be used.

  FIGS. 13 and 14 illustrate an embodiment in which a swellable material such as a hydrogel is used to provide adjustable stiffness to the catheter. In FIG. 13, a portion of the catheter 120 comprises an inner polymer layer 122 and an outer polymer layer 124. Inner polymer layer 122 and outer polymer layer 124 may each independently be formed from any suitable one or more polymers. A gap 126 is disposed between the inner polymer layer 122 and the outer polymer layer 124. Located within the gap 126 is a layer or coating 128 of swellable material. As shown in this figure, the coating 128 is dry.

  In FIG. 14, swelling the coating 128 of swellable material eliminates the gap 126 seen in FIG. By contacting the coating 128 with a suitable liquid, the coating 128 can be swollen. For example, if the coating 128 is a hydrogel, the coating 128 can be swollen by simply contacting the coating 128 with water. In some cases, the gap 126 (FIG. 13) may extend sufficiently proximal to communicate with the hub 22 (see FIG. 1) so that a suitable liquid such as water can be introduced. .

  Examples of suitable swellable materials include hydrophilic polymers. A hydrophilic polymer is a polymer that attracts water molecules or binds to water molecules when the polymer is placed in contact with an aqueous system. Examples of water-containing systems that can provide water molecules that can bind to hydrophilic polymers include blood and other body fluids. When a hydrophilic polymer comes into contact with such a system, the water molecule binds to the polymer by a mechanism such as hydrogen bonding between the water molecule and a substituent or functional group present in or on the polymer. be able to.

  One type of polymer that can be considered hydrophilic is an ionomer polymer. An ionomer polymer is a polymer that is thought to contain ionic bonds between the chains while including covalent bonds between the elements in the chain. An ionomer polymer is a polymer having charged functional groups added to the polymer chain. The charged functional group may be positively charged, in which case the polymer may be referred to as a cationomer. Alternatively, the functional group may be negatively charged, in which case the polymer may be referred to as anionomer.

  Ionomer polymers can be formed using a variety of negatively charged functional groups. The negatively charged functional group may be added to the preformed polymer or the negatively charged functional group is part of one or more monomers used to form the ionomer polymer. May be.

  Examples of suitable negatively charged functional groups include sulfonates and carboxylates. The ionomer polymer in particular contains sulfonate functional groups. These groups are negatively charged and can easily hydrogen bond with a sufficient amount of water when contacted with a source of water such as a system containing water.

  Further examples of suitable materials include nonionic polyether polyurethanes that are commercially available under the name HYDROSLIP®. Another suitable material includes non-ionic aliphatic polyether polyurethanes that are commercially available under the name TECOGEL®. Examples of other suitable nonionic polymers include poly (hydroxy methacrylate), poly (vinyl alcohol), poly (ethylene oxide), poly (n-vinyl-2-pyrrolidone), poly (acrylamide) and other similar Examples include polymers such as substances.

FIGS. 15-17 illustrate embodiments of the present invention in which the catheter can enjoy adjustable stiffness by the use of an outer sheath that can be slidably disposed on the catheter.
FIG. 15 shows a catheter 130 comprising an elongate shaft 132 and a rigid sheath 134 slidably disposed on the elongate shaft 132. The elongate shaft 132 may be a polymer shaft and may comprise a single polymer layer, two polymer layers, or several polymer layers, reinforcing layers, and the like. Any suitable polymer or polymers can be used. The rigid sheath 134 may be formed from any suitable rigid polymer or metal material.

  In FIG. 16, the catheter 136 comprises an elongate shaft 132 as discussed with respect to FIG. A first rigid sheath 138 is slidably disposed on the long shaft 132, and a second rigid sheath 140 is slidably disposed on the first rigid sheath 138. In some cases, each of the first rigid sheath 138 and the second rigid sheath 140 is independently moved distally or proximally on the elongate shaft 132 to provide the desired degree of rigidity. May be. Each of the first rigid sheath 138 and the second rigid sheath 140 may be formed from any suitable rigid polymer or metal material.

  In FIG. 17, the catheter 142 includes an elongate shaft 132 as discussed with respect to FIG. A tapered or frustoconical-shaped rigid sheath 144 is slidably disposed on the elongate shaft 132. The rigid sheath 144 has a narrow end 146 and a wide end 148 so that a gradual change in stiffness can be provided. The rigid sheath 144 may be formed from any suitable rigid polymer or metal material.

  FIG. 18 shows an embodiment of the invention using multiple rigid filaments. Catheter 150 includes an elongate shaft 152. The elongate shaft 152 may be a polymer shaft and may comprise a single polymer layer, two polymer layers, or several polymer layers, reinforcement layers, and the like. A lumen 154 extends through the interior of the elongate shaft 152, and the elongate shaft 152 can be formed from any suitable one or more polymers.

  Catheter 150 includes a number of elongated openings 156 disposed within elongated shaft 152. It can be seen that the elongated opening 156 extends longitudinally within the elongated shaft 152. The elongate openings 156 can be equally spaced around the circumference of the elongate shaft 152. Any number of elongated openings 156 may be provided. At least some of the elongated openings 156 include a stiffening filament 158 slidably disposed within the elongated opening 156.

  Depending on performance requirements, one or more stiffness enhancing filaments 158 can be inserted into, removed from, or slid within the appropriate and corresponding elongated openings 156. Optionally, the stiffness enhancing filament 158 may be a wire formed from any suitable material, such as nitinol, stainless steel, titanium, aluminum, cobalt chrome, or other suitable metal.

  19 and 20 illustrate the use of electroactive polymers in providing variable stiffness to the catheter. FIG. 19 shows a catheter 174 having an elongate shaft 176 with one or more polymer layers. A series of flaps 178 are cut into the elongate shaft 176 and the flaps 178 extend into the lumen 180. At least the flap 178 includes an electroactive polymer. It should be noted that for purposes of illustration, the size of the flap 178 relative to the elongate shaft 176 is exaggerated. In this configuration, which is considered a relaxed configuration, the flap 178 provides a level of flexibility to the elongate shaft 176.

  In FIG. 20, a current is flowing. Accordingly, the flap 178 has been moved from the position where the flap 178 seen in FIG. 19 extends into the lumen 180 to the position where the flap 178 aligns with the elongate shaft 176, thereby The column strength of the shaft 176 is increased.

  Optionally, at least some of the elongate shaft 12 (see FIG. 1) is formed from a layer of electrostatically activatable material such as an electroactive polymer, a polymer including a bucky tube, or perhaps a liquid crystal polymer. Alternatively, it is contemplated that the layer may be provided. It is contemplated that such materials can change the relative stiffness of the catheter containing the material when subjected to an electrical current.

  It should be understood that this disclosure is merely illustrative in many respects. Changes may be made in details, particularly with respect to shape, size, and process arrangement, without exceeding the scope of the invention. The scope of the invention is, of course, defined in the language in which the appended claims are expressed.

1 is a side view of a catheter according to an embodiment of the present invention. 1 is a schematic longitudinal sectional view of a portion of a catheter according to an embodiment of the present invention. FIG. 3 is a longitudinal cross-sectional view of a portion of the catheter of FIG. 1 is a cross-sectional view of a catheter in a relaxed configuration, according to an embodiment of the present invention. The figure which shows the catheter of FIG. FIG. 5 is another view showing the catheter of FIG. 4. 1 is a side view of a catheter in a contracted configuration, according to an embodiment of the present invention. FIG. FIG. 8 is a side view of the catheter of FIG. 7 in an expanded configuration, according to an embodiment of the present invention. 1 is a side view of a catheter according to an embodiment of the present invention. FIG. 6 is another side view of a catheter according to an embodiment of the present invention. FIG. 6 is another side view of a catheter according to an embodiment of the present invention. FIG. 6 is another side view of a catheter according to an embodiment of the present invention. 1 is a schematic cross-sectional view in the longitudinal direction of a catheter according to an embodiment of the present invention. The figure which shows the catheter of FIG. 1 is a side view of a catheter according to an embodiment of the present invention. FIG. 6 is another side view of a catheter according to an embodiment of the present invention. FIG. 6 is another side view of a catheter according to an embodiment of the present invention. 1 is a perspective view of a catheter according to an embodiment of the present invention. 1 is a schematic cross-sectional view in the longitudinal direction of a catheter in a relaxed configuration, according to an embodiment of the present invention. FIG. FIG. 20 shows the catheter of FIG. 19 in an operational configuration, according to an embodiment of the present invention.

Claims (35)

An adjustable catheter comprising a distal region and a proximal region, the catheter comprising:
An elongated polymer shaft extending from the proximal region to the distal region;
An adjustable catheter comprising a first helically cut hypotube disposed within the elongate polymer shaft.   The first helically cut hypotube is capable of translational movement from a relatively proximal position to a relatively distal position, thereby increasing the stiffness of the distal region of the catheter. 2. The adjustable catheter according to 1.   The hypotube cut into the first spiral is rotatably arranged in the elongated polymer shaft, and the rigidity of the hypotube is increased by rotating the hypotube cut into the first spiral. The adjustable catheter of claim 1.   The adjustable catheter of claim 1, further comprising a second helically cut hypotube disposed about the first helically cut hypotube.   The second spiral cut hypotube has a relaxed inner diameter at a relaxed position, and the first spiral cut hypotube has a relaxed outer diameter at a relaxed position; The adjustable catheter of claim 4, wherein the relaxed inner diameter of the second helically cut hypotube is greater than the relaxed outer diameter of the first helically cut hypotube.   The second spiral cut hypotube is rotated by rotating the second spiral cut hypotube relative to the first spiral cut hypotube. 6. The adjustable catheter of claim 5, wherein the hypotube contracts onto the first helically cut hypotube.   The first spiral-cut hypotube is rotated by rotating the first spiral-shaped hypotube relative to the second spiral-cut hypotube. 6. The adjustable catheter of claim 5, wherein a hypotube extends over the second helically cut hypotube.   The adjustable catheter of claim 4, wherein the first helically cut hypotube and the second helically cut hypotube are each independently translatable relative to each other. An adjustable catheter having a distal region defining a distal end and a proximal region defining a proximal end, the catheter comprising:
An elongate polymer shaft defining a lumen extending from the proximal region to the distal region;
A first inflatable tube disposed within the lumen, the first inflatable tube extending from the proximal region to the distal region and disposed at least substantially parallel to the longitudinal axis of the catheter. ,
An adjustable catheter that increases the rigidity of the elongate polymer shaft by inflating the first inflatable tube.   The adjustable catheter of claim 9, wherein the first inflatable tube extends from a proximal position proximate to the proximal end of the catheter to a distal position proximate to the distal end of the catheter.   The adjustment of claim 9, further comprising a second inflatable tube disposed within the lumen, wherein the first inflatable tube and the second inflatable tube are disposed at least substantially parallel to each other. Possible catheter.   The adjustable catheter of claim 11, wherein the first and second inflatable tubes each extend from a proximal region of the catheter to a distal region of the catheter.   The adjustable catheter of claim 11, wherein the first inflatable tube is longer than the second inflatable tube.   The elongate polymer shaft includes an inner layer and an outer layer, the lumen includes an annular lumen defined between the inner layer and the outer layer, and the first inflatable tube is disposed within the annular lumen. The adjustable catheter of claim 9, comprising an elongate annular ring disposed on the body.   The adjustable catheter of claim 14, wherein the elongate annular ring has at least a substantially constant wall thickness.   The adjustable catheter of claim 14, wherein the elongated annular ring has a varying thickness.   The adjustable catheter of claim 14, wherein the first inflatable tube is defined by an inner layer and an outer layer of the elongate polymer shaft. An adjustable catheter having a distal region defining a distal end and a proximal region defining a proximal end, the catheter comprising:
The inner polymer liner;
An outer polymer liner disposed around the inner polymer liner;
A liquid swellable layer disposed between the inner polymer liner and the outer polymer liner;
An adjustable catheter that increases the stiffness of the adjustable catheter by adding liquid to the liquid swellable layer.   The adjustable catheter of claim 18, wherein the liquid swellable layer comprises a water swellable material. In an adjustable catheter comprising a distal region and a proximal region, the catheter comprises
An elongated polymer shaft extending from the proximal region to the distal region;
An adjustable catheter comprising a stiffness enhancing sheath slidably disposed on the elongate polymer shaft, the stiffness enhancing sheath being stiffer than the elongate polymer shaft.   21. The adjustable catheter of claim 20, wherein the stiffness enhancing sheath comprises a polymer having a durometer hardness that is higher than the polymer of the elongated polymer shaft.   21. The adjustable catheter of claim 20, wherein the stiffness enhancing sheath comprises a metal sheath.   21. The stiffness enhancing sheath comprises: a first sheath slidably disposed on the elongated polymer shaft; and a second sheath slidably disposed on the first sheath. The adjustable catheter as described.   24. The adjustable catheter of claim 23, wherein the second sheath is more rigid than the first sheath.   21. The adjustable catheter of claim 20, wherein the stiffness enhancing sheath has a distal end and a proximal end, the distal end having a smaller diameter than the proximal end.   26. The adjustable catheter of claim 25, wherein the stiffness enhancing sheath is frustoconical. In an adjustable catheter having a distal region and a proximal region, the catheter comprises:
An elongated polymer shaft extending from the proximal region to the distal region and comprising a wall;
A plurality of elongated openings disposed in the wall, each having a plurality of elongated openings each extending in the longitudinal direction in the elongated polymer shaft;
An adjustable catheter comprising a plurality of stiffness enhancing filaments slidably disposed within each of the plurality of elongated openings.   28. The adjustable catheter of claim 27, wherein the plurality of stiffness enhancing filaments are comprised of metal wires. In an adjustable catheter comprising a distal region and a proximal region, the catheter comprises
An inner polymer layer comprising one or more electrically actuated stiffness enhancing structures, wherein the inner polymer layer defines a lumen and comprises an outer surface;
An adjustable catheter comprising an outer polymer layer disposed on the inner polymer layer.   The one or more electrically actuated stiffness enhancing structures comprise a polymer flap, the polymer flap having a relaxed position extending into the lumen and an actuated position aligned with the outer surface of the inner polymer layer. Item 30. The adjustable catheter according to Item 29.   30. The adjustable catheter of claim 29, wherein the one or more electrically actuated stiffness enhancing structures contain an electroactive polymer. An adjustable catheter comprising a distal region and a proximal region, the catheter comprising:
It has a long polymer shaft with rigidity,
An adjustable catheter, wherein the stiffness of the elongate polymer shaft can be changed by passing a current through the elongate polymer shaft.   33. The adjustable catheter of claim 32, wherein the elongate polymer shaft contains an electroactive polymer.   33. The adjustable catheter of claim 32, wherein the elongate polymer shaft contains a polymer that includes a bucky tube.   33. The adjustable catheter of claim 32, wherein the elongate polymer shaft contains a liquid crystal polymer.

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